This invention relates to forging and thermoforming to make hollow articles of thermoplastic biaxially oriented resin. An aspect concerns automatic forging and thermoforming of same. An aspect of the invention is an improved carrier for the die in which the workpiece is held during the various shaping processes. An aspect of the invention is an improved unloading means which include mold unlocking means and ejection or article removing apparatus.
The present invention is an improvement on the teachings of U.S. Pat. Nos. 3,739,052, 3,947,204, and 4,005,967 which collectively deal with the forging and thermoforming of articles from a lubricated blank that has been heated to a temperature for biaxial orientation and with tooling for carrying out the forging and thermoforming steps.
The forging operation smashes the blank between hammer and anvil thereby forcing it out into engagement with the die set (die) thereby making what is called a preform characterized by a disc or flat center surrounded by a lip. The preform lip is locked into the die and remains so until the finished article is ejected. The preform is transported while locked into the die to a thermoformng station where it is formed into a hollow article. The temperature of the blank, preform, and article is maintained at a level to permit biaxial orientation. The lip provides a strong mechanical engagement between the preform and the die itself. After being thermoformed, the article is removed still locked in the die to the ejection station where the die is unlocked and article removed.
The present invention improves on the die of U.S. Pat. Nos. 3,947,204 and 4,005,967 by providing means for mechanically rapidly locking and unlocking the die set preparatory to, respectively, forging and later on ejection. The invention also relates to die carrier or support means and to ejection means. One or more sets of dies can be provided. Ordinarily, the requirement of modern day mass production would insist on a plurality of die sets and their respective workpieces being presented at each of the three contemplated stations of this apparatus. The simultaneous use of four sets of dies is described herein for purposes of illustration and example. In the interest of brevity, the mechanism for only one die set will be established, it being understood that the other die sets are similarly, and ordinarily identically, constructed.
The present invention also includes a carrier assembly for mounting the aforesaid die sets and keeping them in alignment while moving same through the various operations and workstations. This carrier assembly preferably includes a set of matched carrier plates containing parts of the die set and also including a locking ring which is rotated responsive to machine position in order to lock the dies. The carrier plates are uniquely supported by carrier support means so as to float with and achieve a die-closing operation conjointly with the locking operation. The carrier plate mounting is such as to confine forging stress to a set of tie rods.
Thus the invention includes a machine for transporting a workpiece to a series of workstations comprising -- a machine frame; a shaft revolvably supported in said frame and having an axis about which it revolves; a carrier assembly for engaging at least one workpiece; a carrier support means mounted betwen and to one of said shaft and said carrier assembly for supporting one of them for motion relative to the other parallel to said axis and for supporting said carrier assembly at a position that aligns said carrier assembly with said workstation upon arrival at the latter.
Another interesting aspect of the invention is the stripping or ejection means which is so designed as to provide sufficient daylight or opening between the lip ring dies so that the finished article can be removed therefrom. As described in further detail below, this opening feature is characterized by an upper carrier plate that has a set of opening lugs which are engaged at the ejection station to pull the upper carrier plate and die completely free of the lower plate and whatever dies it carries. Even though the two plates are thus widely separated the device is so designed as to put the carrier plates and dies carried thereby back together in the correct and very exacting alignment.
Thus the invention includes a machine for removing a lipped article from a carrier assembly that has clamping means that engage at least a portion of the article lip and has transported the workpiece from whence derived the article through shaping procedures comprising -- unclamping means for separating the carrier assembly to disengage said clamping relation and to space apart carrier assembly components by an amount sufficient to permit removal of said article through the space between said spaced apart components; removing means for removing the article from engagement by any component of said carrier assembly and temporarily retaining it within such space; and means for withdrawing said article through said space by which said components are separated.